Deformable integrated-circuit devices have attracted attention due to their ability to adapt to specific geometrical boundary conditions of the operating environment they are used in. For instance, unlike conventional rigid integrated-circuit devices, a deformable integrated-circuit may be bent for installation on a bent surface.
U.S. Pat. No. 6,479,890 discloses deformable integrated-circuit device, which comprises a plurality of substrate islands embedded in a flexible foil. Connection lines are arranged on the flexible foil for electrically connecting the substrate islands. Similarly, U.S. Pat. No. 6,953,982 B1 describes a deformable integrated-circuit device, which is formed of Silicon islands encapsulated in a polyimide film. For fabricating the Silicon islands, Silicon wafers are etched to a desirable thickness by wet etching and then patterned from the backside by reactive ion etching (RIE).
An deformable integrated-circuit device is known from U.S. Pat. No. 6,455,931 B1. A fold structure in the form of folded metal interconnects (conductor tracks) meandering in a plane parallel to the main substrate surface is provided for connecting neighboring substrate islands. This expandable structure is useful for increasing the area between individual circuit components when placing the device in its operating position. However, the meandering conductive track raises issues of mechanical stability during deformation, which increases the risk of unreliability, i.e. device failure. Stability therefore requires conductor tracks of sufficient width, which consume a rather large chip area during fabrication, and in consequence result in a rather expensive device.